The present invention relates generally to optical fibers. More specifically, the present invention pertains to methods of positioning and aligning optical fibers within a fiber optic system. The present invention is particularly, though not exclusively, useful for quickly and accurately inserting optical fibers into fiber ferrules and other fiber alignment devices.
Over the past several decades, the use of optical fibers, or fiber optics, to transmit information on a light beam have become increasingly popular. In fact, much of the information which is transmitted today within the telecommunications industry is done over optical fibers.
A typical single mode (SM) optical fiber has a diameter of approximately 125 microns (125 xcexcm) and is formed with a glass core with a diameter of about ten microns (10 xcexcm). As a result, these optical fibers are rather flexible, yet must be positioned to a very high degree of precision.
As a result of the widespread use of optical fibers, and the fact that the typical optical fibers are very small and flexible, the handling, positioning and termination of these fibers represents a significant challenge to manufacturers of high quality fiber-optic products. Moreover, because some optical equipment incorporates assemblies having many optical fibers that must all be positioned to within a few microns, or inserted into fiber receptacles, or ferrules, this challenge often represents a significant manufacturing problem. The positioning of optical fibers is even more difficult when attempting to position the fibers in blind holes, or when attempting to automate the manufacturing process.
The use of a vacuum to facilitate the insertion of optical fibers greatly simplifies the automated assembly process. In fact, the mechanical alignment tolerances typically experienced in fiber optic manufacturing may be reduced to hundreds of microns, so insertion of fibers into blind holes, typically a most challenging assembly using current approaches, may be easily automated. If conventional ferrules are used, a nozzle end or indent is typically used to guide the fiber. This invention eliminates the need for these nozzles or indented portions, and is even applicable to flat entrance holes.
In a typical application, an optical fiber is positioned for insertion into a hole within about 0.2 mm to 0.3 mm, and held about 50 mm from the end of the fiber. As the fiber is advanced toward the hole, the airstream converging into the hole acts to pull the fiber into alignment with the hole. Consequently, the fiber can be brought near the hole very rapidly, and because the fiber is flexible, the fiber will always go directly into the hole. Experiments have been conducted under microscope observation, and the principle has been repeatedly tested and the sequence observed in each assembly process.
In an application where a partial vacuum may be applied to an alignment plate having a number of alignment holes, a fiber clamp having multiple optical fibers may be positioned such that all of the optical fibers in the clamp may be inserted into the alignment plate simultaneously. As a result, large scale assembly of such delicate and flexible optical fibers, while maintaining a very high level of precision, may be achieved and represents a significant advantage over the current state of the art.